Evaluation of five simple rapid HIV assays for potential use in the Brazilian national HIV testing algorithm

Review of HIV Self Testing Technologies and Promising Approaches for the Next Generation

The ability to self-test for HIV is vital to preventing transmission, particularly when used in concert with HIV biomedical prevention modalities, such as pre-exposure prophylaxis (PrEP). In this paper, we review recent developments in HIV self-testing and self-sampling methods, and the potential future impact of novel materials and methods that emerged through efforts to develop more effective point-of-care (POC) SARS-CoV-2 diagnostics. We address the gaps in existing HIV self-testing technologies, where improvements in test sensitivity, sample-to-answer time, simplicity, and cost are needed to enhance diagnostic accuracy and widespread accessibility. We discuss potential paths toward the next generation of HIV self-testing through sample collection materials, biosensing assay techniques, and miniaturized instrumentation. We discuss the implications for other applications, such as self-monitoring of HIV viral load and other infectious diseases.

Performance of commercially available HIV in vitro diagnostic assays: A systematic review and meta-analysis

Efficient and fast detection of HIV infection is required to make the diagnosis more robust. Use of in vitro HIV diagnostic assays based on different methods are growing rapidly. To maintain quality and further upgradation, regular performance evaluation is required. Due to presence of huge number and types of commercially available kits, choice of implementation varies differentially. The present systematic review and meta-analysis is aimed to address the diagnostic performance of commercially available in vitro HIV assays in terms of pooled sensitivity, specificity, Positive Likelihood Ratio, Negative Likelihood Ratio, area under hierarchical summary receiver operating characteristic curve and diagnostic odds ratios, in global scenario. Total of 18 articles with 35 in vitro diagnostic serological assays including 29,713 samples were subjected for the present pooled analysis. In spite of higher heterogenicity [I² = 93.5%, Q = 520.95, df = 34 (p = 0.0000), τ² = 9.7464], the pooled sensitivity and specificity of the diagnostic serological assays were observed ≥ 98%.

Performance evaluation of eight rapid tests to detect HIV infection: A comparative study from Brazil

Rapid tests (RTs), also known as point-of-care tests, usually release results within 30 minutes with no need for a qualified staff, equipment, or laboratory structure. The Brazilian Ministry of Health published a resolution in 2013, recommending the use of RTs for the diagnosis of HIV infection, where one positive RT must be followed by another different RT. This was meant to increase the chance of proper diagnosis in specific settings and special populations. However, data comparing and validating the different HIV RTs available in Brazil are scarce. Therefore, the present study seeks to evaluate eight anti-HIV RTs available in the Brazilian market regarding their analytical performance: sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and accuracy. We also evaluated the agreement between kits (Kappa index) and the quality of the reading pattern of the tests. This was an observational, analytical, and concordance study, in which previously defined positive and negative samples, based on their serological pattern for anti-HIV antibodies (chemiluminescent immunoassay-ECLIA-used as screening and Western Blot used as the confirmatory test) were tested. Analytical performance and Kappa index were calculated, considering a 95% CI and p<0.05. This study identified differences in the performances of the eight tested kits. Six out of eight RTs showed good performance and can be used in the routine laboratory and health care units as screening tests. Regarding the quality of the RT band reading pattern, two brands had several samples showing quite faint bands, thus compromising its use in clinical and laboratory settings.

A generalizable method for estimating duration of HIV infections using clinical testing history and HIV test results

OBJECTIVE

To determine the precision of new and established methods for estimating duration of HIV infection.

DESIGN

A retrospective analysis of HIV testing results from serial samples in commercially available panels, taking advantage of extensive testing previously conducted on 53 seroconverters.

METHODS

We initially investigated four methods for estimating infection timing: method 1, 'Fiebig stages' based on test results from a single specimen; method 2, an updated '4th gen' method similar to Fiebig stages but using antigen/antibody tests in place of the p24 antigen test; method 3, modeling of 'viral ramp-up' dynamics using quantitative HIV-1 viral load data from antibody-negative specimens; and method 4, using detailed clinical testing history to define a plausible interval and best estimate of infection time. We then investigated a 'two-step method' using data from both methods 3 and 4, allowing for test results to have come from specimens collected on different days.

RESULTS

Fiebig and '4th gen' staging method estimates of time since detectable viremia had similar and modest correlation with observed data. Correlation of estimates from both new methods (3 and 4), and from a combination of these two ('two-step method') was markedly improved and variability significantly reduced when compared with Fiebig estimates on the same specimens.

CONCLUSION

The new 'two-step' method more accurately estimates timing of infection and is intended to be generalizable to more situations in clinical medicine, research, and surveillance than previous methods. An online tool is now available that enables researchers/clinicians to input data related to method 4, and generate estimated dates of detectable infection.

Evaluation of Blood-Based Antibody Rapid Testing for HIV Early Therapy: A Meta-Analysis of the Evidence

Background

Western blot (WB) assay is considered the gold standard test for HIV infection confirmation. However, it requires technical expertise and is quite time-consuming. WHO recommends blood-based rapid diagnosis to achieve same-day test and treatment. However, this rapid testing strategy has not been promoted worldwide due to inadequate research evaluating the effectiveness of rapid tests (RTs) as an alternative confirmatory HIV test for WB. This study aims to compare the diagnostic performance of rapid HIV tests compared with WB.

Methods

PubMed and Web of Science were searched for publications on rapid HIV tests using blood specimen. A meta-analysis was performed to quantitatively evaluate the diagnostic performance of rapid HIV tests compared with the WB assay in terms of pooled sensitivity, specificity, area under summary receiver operating characteristic (SROC) curve, and diagnostic odds ratio (DOR).

Results

Twenty articles involving 27,343 fresh specimens for rapid HIV tests were included in the meta-analysis. Regarding Capillus HIV-1/HIV-2, the pooled sensitivity, specificity, area under SROC curve, and DOR derived from six studies were 0.999 (95% CI, 0.956-1.000), 0.999 (95% CI, 0.991-1.00), 1.00 (95% CI, 0.99-1.00), and 1.0 × 10⁶ (95% CI, 2.6 × 10⁴-3.9 × 10⁷) compared with the WB assay, respectively. With respect to Determine HIV-1/2, the pooled sensitivity, specificity area under SROC, and DOR derived from eight studies were 1.00 (95% CI, 0.789-1.000), 0.992 (95% CI, 0.985-0.996), 1.00 (95% CI, 0.99-1.00), and 1.8 × 10⁶ (95% CI 406.049-7.8 × 10⁹) compared with the WB assay, respectively. Regarding two-step serial RTs, the pooled sensitivity, specificity area under SROC, and DOR derived from eight studies were 0.998 (95% CI, 0.991-1.000), 0.998 (95% CI, 0.994-0.999), and 1.00 (95% CI 0.99-1.00) compared with the WB assay, respectively.

Conclusion

Our meta-analysis results may provide evidenced-based support for substituting RT for WB. Blood-based rapid HIV tests have comparable sensitivity and specificity to WB for HIV early therapy.

Understanding low sensitivity of community-based HIV rapid testing: experiences from the HPTN 071 (PopART) trial in Zambia and South Africa

Introduction: Population-wide HIV testing services (HTS) must be delivered in order to achieve universal antiretroviral treatment (ART) coverage. To accurately deliver HTS at such scale, non-facility-based HIV point-of-care testing (HIV-POCT) is necessary but requires rigorous quality assurance (QA). This study assessed the performance of community-wide HTS in Zambia and South Africa (SA) as part of the HPTN 071 (PopART) study and explores the impact of quality improvement interventions on HTS performance.

Methods: Between 2014 and 2016, HIV-POCT was undertaken within households both as part of the randomly selected HPTN 071 research cohort (Population Cohort [PC]) and as part of the intervention provided by community HIV-care providers. HIV-POCT followed national algorithms in both countries. Consenting PC participants provided a venous blood sample in addition to being offered HIV-POCT. We compared results obtained in the PC using a laboratory-based gold standard (GS) testing algorithm and HIV-POCT. Comprehensive QA mechanisms were put in place to support the community-wide testing. Participants who were identified as having a false negative or false positive HIV rapid test were revisited and offered retesting.

Results: We initially observed poor sensitivity (45–54%, 95% confidence interval [CI] 31–69) of HIV-POCT in the PC in SA compared to sensitivity in Zambia for the same time period of 95.8% (95% CI 93–98). In both countries, specificity of HIV-POCT was >98%. With enhanced QA interventions and adoption of the same HIV-POCT algorithm, sensitivity in SA improved to a similar level as in Zambia.

Conclusions: This is one of the first reports of HIV-POCT performance during wide-scale delivery of HTS compared to a GS laboratory algorithm. HIV-POCT in a real-world setting had a lower sensitivity than anticipated. Appropriate choice of HIV-POCT algorithms, intensive training and supervision, and robust QA mechanisms are necessary to optimize HIV-POCT test performance when testing is delivered at a community level. HIV-POCT in clients who did not disclose that they were on ART may have contributed to false negative HIV-POCT results and should be the topic of future research.

HIV point of care diagnosis: preventing misdiagnosis experience from a pilot of rapid test algorithm implementation in selected communes in Vietnam

INTRODUCTION

In Vietnam, HIV testing services had been available only at provincial and district health facilities, but not at the primary health facilities. Consequently, access to HIV testing services had been limited especially in rural areas. In 2012, Vietnam piloted decentralization and integration of HIV services at commune health stations (CHSs). As a part of this pilot, a three-rapid test algorithm was introduced at CHSs. The objective of this study was to assess the performance of a three-rapid test algorithm and the implementation of quality assurance measures to prevent misdiagnosis, at primary health facilities.

METHODS

The three-rapid test algorithm (Determine HIV-1/2, followed by ACON HIV 1/2 and DoubleCheckGold HIV 1&2 in parallel) was piloted at CHSs from August 2012 to December 2013. Commune health staff were trained to perform HIV testing. Specimens from CHSs were sent to the provincial confirmatory laboratory (PCL) for confirmatory and validation testing. Quality assurance measures were undertaken including training, competency assessment, field technical assistance, supervision and monitoring and external quality assessment (EQA). Data on HIV testing were collected from the testing logbooks at commune and provincial facilities. Descriptive analysis was conducted. Sensitivity and specificity of the rapid testing algorithm were calculated.

RESULTS

A total of 1,373 people received HIV testing and counselling (HTC) at CHSs. Eighty people were diagnosed with HIV infection (5.8%). The 755/1244 specimens reported as HIV negative at the CHS were sent to PCL and confirmed as negative, and all 80 specimens reported as HIV positive at CHS were confirmed as positive at the PCL. Forty-nine specimens that were reactive with Determine but negative with ACON and DoubleCheckGold at the CHSs were confirmed negative at the PCL. The results show this rapid test algorithm to be 100% sensitive and 100% specific. Of 21 CHSs that received two rounds of EQA panels, 20 CHSs submitted accurate results.

CONCLUSIONS

Decentralization of HIV confirmatory testing to CHS is feasible in Vietnam. The results obtained from this pilot provided strong evidence of the feasibility of HIV testing at primary health facilities. Quality assurance measures including training, competency assessment, regular monitoring and supervision and an EQA scheme are essential for prevention of misdiagnosis.

Human Immunodeficiency Virus (HIV) Separation and Enrichment via the Combination of Antiviral Lectin Recognition and a Thermoresponsive Reagent System

PURPOSE

In order to improve the detection limit of existing HIV diagnostic assays, we explored the use of a temperature-responsive magnetic nanoparticle reagent system in conjunction with cyanovirin-N for HIV recognition to rapidly and efficiently concentrate viral particles from larger sample volumes, ~ 1 ml.

METHODS

Cyanovirin-N (CVN) mutant, Q62C, was expressed, biotinylated, and then complexed with a thermally responsive polymer-streptavidin conjugate. Confirmation of protein expression/activity was performed using matrix assisted laser desorption/ionization (MALDI) and a TZM-bl HIV inhibition assay. Biotinylated CVN mutant recognition with gp120 was characterized using surface plasmon resonance (SPR). Virus separation and enrichment using a thermoresponsive magnetic nanoparticle reagent system were measured using RT-PCR.

RESULTS

Biotinylated Q62C exhibited a KD of 0.6 nM to gp120. The temperature-responsive binary reagent system achieved a maximum viral capture of nearly 100% HIV, 1 × 10(5) virus copies in 100 μl, using pNIPAAm-Q62C within 30 minutes. Additionally, the same reagent system achieved nearly 9-fold enrichment by processing a 10-times larger sample of 1000 μl (Fig. 3).

CONCLUSION

This work demonstrated a temperature-responsive reagent system that provides enrichment of HIV using antiviral lectin CVN for recognition, which is potentially amenable for use in point-of-care settings.

Development of Monoclonal Antibodies against HIV-1 p24 Protein and Its Application in Colloidal Gold Immunochromatographic Assay for HIV-1 Detection

Human immunodeficiency virus type 1 (HIV-1) p24 protein is the most abundant viral protein of HIV-1. This protein is secreted in blood serum at high levels during the early stages of HIV-1 infection, making it a biomarker for early diagnosis. In this study, a colloidal gold immunochromatographic assay (GICA) was established for detecting p24 protein using mouse monoclonal antibodies (mAbs). The HIV-1 p24 protein was expressed in E. coli strain BL21 and the purified protein was used to immunize mice. Stable hybridoma cell lines secreting anti-p24 monoclonal antibodies were obtained after ELISA screening and subcloning by limiting dilution. 34 different capture and labeling mAb pairs were selected by a novel antibody-capture indirect sandwich ELISA and then applied in GICA to detect p24 protein. The GICA method has a limit of detection (LOD) of 25 pg/mL and could detect p24 protein in all 10 positive samples obtained from the National Reference of HIV-1 p24 antigen. Out of 153 negative samples tested, 3 false positives results were obtained. The overall specificity of this test was 98.03%. The good sensitivity and specificity of this method make it a suitable alternative to provide a more convenient and efficient tool for early diagnosis of HIV infection.

HIV Care Continuum Applied to the US Department of Veterans Affairs: HIV Virologic Outcomes in an Integrated Health Care System

BACKGROUND

The Department of Veterans Affairs (VA), the largest integrated HIV care provider in the United States (US), used the HIV Care Continuum to compare clinical care within the VA HIV population with the general US HIV population and to identify areas for improvement.

METHODS

National data from the VA's HIV Clinical Case Registry were used to construct measures along the Continuum for Veterans in VA care diagnosed with HIV by June 2013 and alive by December 31, 2013. Comparisons were made to recent estimates for the same measures for the US HIV population. Additional comparisons were performed for demographic subgroups of sex, race/ethnicity, and age.

RESULTS

Of 25,480 Veterans diagnosed with HIV, 77.4% were engaged in care compared with 46.3% in the US population diagnosed with HIV (P < 0.001). Seventy-three percent of Veterans diagnosed with HIV received antiretroviral therapy compared with 43% of the US population diagnosed with HIV (P < 0.001). Nearly two-thirds (65.3%) of HIV-diagnosed Veterans had suppressed HIV viral loads compared with 35.0% of the US population diagnosed with HIV (P < 0.001).

CONCLUSIONS

The VA health care system performed better at every stage of the HIV Care Continuum compared with the general US estimates. Comparable high rates with some variation were noted among the demographic groups in the VA cohort. The high viral suppression rate in VA, which was almost double the estimate for the HIV-diagnosed US population, demonstrates that improved outcomes along the HIV Care Continuum can be achieved in a comprehensive integrated health care system.

Home-based counseling and testing for HIV and syphilis - an evaluation of acceptability and quality control, in remote Amazonas State, Brazil

OBJECTIVE

Home-based, voluntary counselling and testing (HBCT) can help scale up early diagnosis. We aimed to evaluate the acceptance of HBCT for HIV and syphilis, estimate the prevalence among home-tested individuals and assess the performance of point-of-care testing by health staff using dried tube specimens (DTS) in a remote municipality of the Amazon region.

METHODS

Community health teams conducted door-to-door outreach in the urban area of São Gabriel da Cachoeira, Amazonas. HBCT for HIV and syphilis was offered to all residents aged ≥15 years. To provide an external quality assurance (EQA) of the healthcare workers' (HCW') ability to perform testing, DTS panels of reference samples were reconstituted and tested by the workers.

RESULTS

HBCT was offered to 1752 individuals and accepted by 1501 (85.6%). Those tested had a median age 32.0 years, 64.4% were women and 85.1% were indigenous; none were previously tested using a rapid test. The prevalence of HIV was 0.37% in men and 0.0% in women; the prevalence of syphilis was 1.12% in men and 2.69% in women. Eleven HCW tested 44 DTS samples for HIV and 44 for syphilis. EQA testing revealed that workers interpreted 55.8% and 90.7% of HIV and syphilis reference samples correctly.

CONCLUSIONS

HBCT was acceptable and successful in reaching untested individuals. However, there were concerns with the quality of test performance, highlighting the need for continual evaluation and retraining of community HCW. As Brazil scales up HIV and syphilis testing, our findings highlight how HBCT can maximise coverage in similar remote areas and improve knowledge about prevalence of these infections.